feat(ui): remove the dead warden role from the Compass UI

[seal-agent]

Warden is dead — the role no longer exists in the product, so its role/fixture/comms/pip and the wardenPaused agent-state producer were dead code in a pre-dogfood codebase. This removes all of it.

Refs SEA-1892. Resolves the SEA-1876 Q4 warden-purple design fork (the warden pip is deleted, so there is no warden-purple question left; the other 4 --purple consumers are handled in the DS token-cutover design record).

Change (12 files, +40/-158, all apps/ui/src)

• stub-data.ts — AgentRole union drops "warden" ("supervisor" | "worker"); delete the acc-warden fixture; reword a stub issue title.
• agent-state.ts — delete the wardenPaused refinement + its return "paused" producer. paused stays a valid AgentState (union member, --st-paused token, .state-dot[data-state="paused"] CSS) per Matt's ruling — it is now directly-settable-only, no longer warden-derived.
• comms-stub.ts — delete the warden DM topic + 3 matt↔warden messages; reword the fleet-snapshot text. (dm-warden channel auto-derives from STUB_AGENTS and drops with the fixture.)
• LeftSidebar.tsx — collapse the role-pip glyph to ◆ (supervisor is the only remaining non-worker).
• app.css — delete the .role-pip[data-role="warden"] rule; reword a header comment. --purple def + its 4 other consumers untouched.
• 5 test files — delete the wardenPaused override block (tested deleted behavior); repoint acc-warden usages to live fixtures (acc-supervisor for owns-nothing/zero-terminal intent, acc-cook for the fleet-pane home-DM render, acc-livingstone for the pin-order constant) preserving each test's original intent.

Verification

• 0 case-insensitive warden refs remain under apps/ui/src.
• Gate green in a colocated clone with .git present (env-secrecy tests shell git): tsc 0, biome 0, bun test --conditions browser = 699 pass / 0 fail (was 723 on main; the 24-test drop is exactly the deleted wardenPaused coverage).
• Rebased onto current main; CI CI completed/SUCCESS at head f3ce0220; merge state CLEAN/MERGEABLE.

Review

Sole adversarial review: floor-clean — 0 high, 0 medium, 2 low, 2 nit. The reviewer independently confirmed every acc-warden repoint preserves its test's intent, the projection totality invariant holds, and the producerless-paused state is Matt's intentional ruling (not a bug). The 2 nits (both terminal tests now use acc-supervisor; a comment wording tweak) are below-floor cosmetic and deliberately not committed.

Open Questions (parked for Matt — non-blocking)

• paused render path is now test-uncovered. With the warden producer gone and no fixture agent carrying lifecycle: "paused", nothing renders a paused dot, so the retained render path is covered only by the VALID_DOTS membership guard, not an actual render. This is coherent with the keep-paused ruling; the reviewer flagged (and I agree) that adding a lifecycle: "paused" fixture to keep the path exercised is a fixture/design choice for Matt, not a mechanical fix — parked rather than done unilaterally.

[linear-code]

SEA-1892